class Adder {
    name = 'adder';
}
class CustomAdder extends Adder {
    x;
    y;
    constructor(x, y) {
        super();
        this.x = x;
        this.y = y;
    }
    add() {
        return this.x + this.y;
    }
    addTwice() {
        return (this.x + this.y) * 2;
    }
}
const adder = new CustomAdder(1, 2);
console.log(adder.add(), adder.x, adder.y);
console.log(adder.name);
console.log(adder.addTwice());
